Necrotizing Fasciitis

Audience This scenario was developed to educate emergency medicine residents and medical students on the diagnosis and management of necrotizing fasciitis (NF). Introduction Necrotizing fasciitis is an uncommon and life-threatening deep tissue infection. Clinical presentations may range from subtle non-specific signs and symptoms to multi-organ failure.1 Signs and symptoms suggestive of necrotizing fasciitis include skin necrosis, hemorrhagic bullae, pain out of proportion, and erythema progressing beyond margins.2 Radiographs may show dissecting gas along fascial planes in the absence of trauma, but this is not a sensitive finding and may present late in the disease course. Ultrasound may demonstrate soft-tissue gas, fascial irregularity, and diffuse fascial thickening. Computerized tomography (CT) is the imaging modality of choice. The sensitivity of diagnosing necrotizing infections on CT is 80% and the diagnosis should not be excluded by lack of soft tissue gas.3 While laboratory findings may reveal an elevated C-reactive protein (CRP) level,4 other laboratory findings may be used in conjunction to calculate a laboratory risk indicator for necrotizing soft tissue infections score (LRINEC) value which may predict morbidity and mortality.5 Providers must treat empirically without delay or confirmation through laboratory results or imaging studies. Treatment should be initiated in a timely fashion, including broad-spectrum antibiotics, intravenous fluids, and urgent discussion with surgical consultants to evaluate for prompt operative management.6 Educational Objectives At the conclusion of the simulation session, learners will be able to: 1) Describe the spectrum of clinical presentations of necrotizing fasciitis. 2) Identify the microbial etiology of necrotizing fasciitis. 3) Describe the empiric antibiotics appropriate for necrotizing fasciitis. 4) Describe benefits and limitations of various imaging studies when working up necrotizing fasciitis. Educational Methods This session was conducted using high-fidelity simulation, followed by a debriefing session reviewing case progression, differential diagnoses, management, and disposition. This scenario may also be run as an oral boards case. Research Methods Our residents are provided a survey at the completion of the debriefing session so they may rate different aspects of the simulation, as well as provide qualitative feedback on the scenario. Results Residents were also asked to rate the overall clinical experience of the simulation activity on a scale of 1 to 7; 1 being extremely ineffective/detrimental and 7 being extremely effective/outstanding. A total of 10 resident participants responded to the survey. This simulation scenario had a median rating of 7 for the instructor setting the stage and for instructors introducing themselves and explaining the learning objectives. A median rating of 7 was also given in explaining the strength and weakness of the simulation scenario, which was key to its clinical application. Residents voiced appreciation that the clinical presentation was unique and that it required a thorough physical exam, including visualizing the affected area. As the patient presented rather early in his clinical course, they felt the diagnosis was more difficult to ascertain, as rhabdomyolysis and cellulitis were also on their differentials. Discussion This is a cost-effective method to review a presentation of necrotizing fasciitis early in the disease course. Since the patient did not have a high fever or toxic appearance, participants demonstrated some hesitation in definitively diagnosing a necrotizing infection. We will continue to provide simulation scenarios with more subtle or early presentations to challenge residents’ diagnostic skills. Topics Medical simulation, soft tissue infection, necrotizing fasciitis, infectious disease.

Initial presentation: Patient is a 34-year-old male with history of type 2 diabetes mellitus who presents with right thigh pain for two days.
The pain initially started as cramps following a 5K race two days ago, and it has progressively gotten worse throughout the day. Patient is diaphoretic and in obvious pain.
How the scenario unfolds: Patient is a 34-year-old male who presents from home with right leg pain. Participants should expose the patient's right leg. Bloodwork will reveal leukocytosis and elevated lactate. Participants should initiate IV fluids and broad-spectrum antibiotics, including vancomycin, Zosyn Ò and clindamycin. Participants should have high suspicion for NF and consult surgery emergently. Participants should not allow imaging to delay surgical evaluation. If there is a delay in fluid resuscitation, empiric antibiotics, or STAT surgical consultation, the patient will become more hypotensive and tachycardic. If these actions are not all performed, the patient will continue to decompensate. Once all of these actions have been performed, tachycardia and hypotension will improve, but the patient will still require emergent operative debridement and subsequent ICU admission. Team should voice concern for NF, initiate antibiotics and consult surgery.
Surgery consultant should request imaging be performed before they examine the patient. Participants must then clearly voice their concern for necrotizing fasciitis and need for STAT surgical consult before they agree to see the patient prior to imaging results. If the participants do not clearly relay their concerns, surgery will tell them they'll call them back later and will hang up.

Monitor display (vital signs)
If the team does not voice concern for necrotizing fasciitis or they do not consult surgery by minute 08:00, go to B vitals.
If the team is not insistent on a STAT surgical consultant OR if antibiotics are not given by 08:00, patient will become more hypotensive at minute 08:00 (A vitals) with further decompensation at minute 10:00 (B vitals) until these are performed.
If team requests a STAT surgical consult and orders empiric antibiotics by 08:00, vitals will remain unchanged from previous step (C or D vitals, depending on IV fluid bolus administered).

Necrotizing Fasciitis
Pearls: • NF can be due to mono or polymicrobial infections, including gram positive organisms (GAS, Staph A, MRSA), gram-negative bacilli, and spore-or toxin-producing anaerobes. Clinical presentation may range from subtle deep tissue disease to fulminant presentation with sepsis or multi-organ failure. • The most frequently reported presenting signs and physical exam findings are fever, erythema, swelling, pain out of proportion, and/or pain beyond visualized margin of infection. • Differential diagnoses may include deep vein thrombosis, cellulitis, hematoma, clostridial myonecrosis, pyomyositis, and pyoderma gangrenosum. • Risk factors for necrotizing fasciitis include immunosuppressive conditions (diabetes, cirrhosis, HIV), malignancy, alcoholism, recent surgery or trauma. • Diabetes mellitus is the most common predisposing factor associated with increased mortality, increased hospital length of stay, and limb amputation. • Disease course includes an evolution of symptoms over hours or a couple of days.
Symptom development may be initially subtle but progress rapidly. • The widely known "hard" clinical signs of bullae, necrotic tissue, anesthesia, and subcutaneous emphysema are more suggestive of necrotizing infection, but these are rare and late findings of the disease. Absence of these signs is not sufficient to rule out necrotizing infection. • Prognosis is guarded, with reported mortality rates ranging from the 20s-40s percent.
• It is critical to have a high suspicion of index for necrotizing disease. A thorough history and physical exam are key in making an early clinical diagnosis. • While the LRINEC score may predict morbidity and mortality, sensitivity is limited.
Further studies are needed to support its widespread use, and a low score should not exclude cases from receiving expedited, aggressive care. • The most commonly reported anatomical site for necrotizing infections is the lower extremity. • Surgical evaluation for definitive surgical treatment is indicated if necrotizing infection is clinically suspected. Diagnostic imaging should not delay surgical evaluation. • In addition to surgical intervention, early fluid resuscitation and IV antibiotics with broad spectrum coverage have been shown to significantly improve mortality.